Fuel injection valve apparatus



Oct. 26, 1943.

, o. FUSCALDQ' FUEL INJECTION VALVE APPARATUS Original Filed April 14, 1937 Fig.3 v

INVENTOR: O/fawa Fusca/ao;

WKMWLS/l TTORNEYS,

Patented Oct. 26, 1943 1 FUEL INJECTION VALVE APPARATUS Ottavio Fuscaldo, Milan, Italy; vested in the Alien Property Custodian Original application April 14, 1937, Serial No.

Divided and this application March 16, 1940, Serial No. 324,354. In Italy April 18,

2 Claims. (Cl. 137-139) The present invention is a fuel injection valve apparatus for internal combustion engines, the instant application being a division of applicant's copending application Serial No. 136,733, filed April 14, 1937.

The method of operation of the invention consists essentially in the fact that the liquid fuel is made to enter into the engine through electromagnetically controlled injecting means, within which the fuel is maintained under pressure in such a way that the difference between the pressure ofthe fuel and that of the chamber into which it is injected will be practically constant.

The apparatus comprises electromagneticall'y controlled injecting means and means adapted to impart to the fuel, within theinjectlon means, such a pressure that it will pass into the engine as soon as the injection valve opens, owing to a practically constant difference of pressure.

According to the invention it- Will be possible to predetermine the duration ofthe injection and to adjust its phases within the cycle.

These and the specific characteristics of the invention will now be explained with special reference to the drawing, given merely indicatively as examples, and not limitative as to the scope of the invention.

Fig. 1 is a schematic view of a device suitable for low pressures embodying the invention.

Fig. 2 shows a practical embodiment of the in vention partly in central section view; and

Fig. 3 shows in similar, view an embodiment with differential piston, particularly suitable for high pressures. I

As may be seen from Fig. 1, the devic comprises: the electromagnetically governed injector repeated for each cylinder; the current distributor for the governing of the several injectors on the motor, and which varies in its details according to the number of injectors it has to serve; the feed ing apparatus of thefuel under pressure for the is, as aforesaid, according to the cases, into the feed conduit or into the compression chamber).

See Figs. 1, 2 and 3. .Its nozzle 9 is normally closed by an internal valve l which is adapted to open it instantaneously by the attraction of a solenoid l3 when a current is supplied by the of a spring l2 when the current d'scontinues.

The injector is continuously led with fuel under pressure out of a supply or manifold which in the case of explosion motors may be an accumulative fuel tank under constant pressure, or, in the case of internal combustion motors may be a particular device as described hereinbelow. As the fuel, in consequence of the pressure to which it is subjected, is always ready to issue from the D injector, the electromagnetic control ensures that the opening and closing of the injection valve will be instantaneous, and that the duration, variation and the timing of the phases of the injection will be of the'hlghest precision at all speed ranges. As far as the effective pressure during the injection is concerned (that is, the difference between the absolute pressure of the liquid that is to be injected and that of the air into which it is injected), it is maintained substantially constant under the constant pressure with the apparatus of the first case (explosion motors), and will be automatically rendered constant when executed with the special apparatus in the second case (internal combustion motors).

The advantages of the described injection method are of the utmost practical importance as they permit one to suppress or to diminish to a high degree the defects of the systems at present in use: that is, they permit a considerable increase of the rate of combustion and, consequently, of the thermic efficiency and of the possible speed of the motor; a very precise dosing of the fuel, particularly in the multi-cylinder motors, and, consequently, a regular running at low consump'tion; a great variability of the dosage up to extraordinarily small volumes, and, therefore, a great elasticity of operation and an idle running at a rather reduced speed; a reduction of the air excess and, consequently, of the effective specific stroke volume and a reduction of weight.

aeeaeoe a valve stem located in the fuel chamber and is tion l of the valve stem is provided with a series.

of longitudinal grooves or liquid displacement passages l8 extending the full: length of 'said portion so as, on the one hand to enable the fuel to flow, freely past said portion, and, on the other hand, to enable the valve stemto move freely without hindrance by the fuel.

At its opposite or right end, the valve stem is.

provided with another enlarged portion i of magnetic material as for instance iron, this portion having a sliding fit with the solenoid and constituting an armature therefor. When the valve is closed, the rightmost end of the enlarged 3 portion i is located in slight spaced relation with a fixed core portion id of the solenoid and I which projects inwardly from a casing, or shroud ll, housing the solenoid and screwed upon the valve casing. .The portion of the armature carried by the valve stem is provided with a cylindrical recess i opened atthe end, and in which there is located a; spring l2 reacting between the base of said recess and the inner end of the fixed core portion iii, the spring serving to urge the valve to its closed position.

Since the solenoid shroud ii is of magnetic adapted to partake of a short longitudinal movement in the chamber in its movements between its opened and closed positions. The valve stem is guided in its movements, at its valve end by a head having longitudinally disposed liquid displacement passages and at its other end by a secand head likewise ha ing liquid displacement passages, said second head constituting an arm'ature of a solenoid which surrounds the same, the 'solenoid in addition having .a centrally located fixed core in longitudinal alignment with the armature. The fixed core is supported by or formed integral with a shroud or casing surrounding the solenoid so that except fora slight gap existing-between the armature and the fixed core when the valve stem' is in a position closing the valve, the solenoid has a complete magnetic circuit. of which the movable armature carried by the valve stem forms a part. The invention further contemplates-the provision of means for energizing and deenergizingthe solenoid periodically to regulate the timed injection of fuel into the combustion chamber. When the solenoid is energized, the armature, and consequently the valve stem on which it is mounted, is moved from valve closing position to valve opening position, the latter position being determined by the banking of the armature against the fixed solenoid material, there will be a complete path of mag netic material for the flux of the solenoid, broken only by the slight gap between the core portion carried by the casing and the armature carried 1 by the valve stem. Liquid displacement passages G5 at the base of the recess in the armature portion i permit the free fiow of fuel between the valve chamber and the gap just referred-to.

"According to the arrangement just described,"

when the solenoid i3 is energized, the armature l carried by the valve stem will move instan ed as to allow the discharge of fuel into the comtaheously (against the reaction of the spring l2) -tb"close the. gap and in doing so will eifectan instantaneous and completeopening of the valve j'bustion chamber 3 5. And when the solenoid is" ,deenergized, the spring l2 will act instantaneous- A ly'to move the valve to its closed position, thus I cutting off the supply of'fuel to the combustion chamber. Because of the liquid displacement passages it in the armature and the grooves or li'quid displacement passages to in the -enlarged portion 1 near the left end of the'valve stem, it will be apparent that the valve assembly is in efiec't floating 'freely in the fuel and that there is no pumping action which, on the one hand,

would retard the movements of the valve to its opened or closed positions, or, on the other hand one electromagnetically controlled injection valve for each cylinder in the engine.

Briefly then, thispart of the present improvement consists in providing for each cylinder of a multi-cylinder internal combustion engine, 'a liquid fuel chamber from which liquid fuel is delivered under pressure to the combustion chamber of the cylinder through a valve seat and iniection nozzle, the imection of fuel through the nozzle'being controlled by a valve which includes core when the gap therebetween has been closed and, when the solenoid is deenergilzed, a spring device reacting between'the armature and the fixed core restores the valve'stem to valve closing position which; of course,=is determined by the seating'of the valve itself. The liquid'dis-- placement passageways in the stem guiding head singl cylinder motor. A drum Ztma'deofan insulatingmaterialturns with a shaft 22 rotatingsnithin' -the bearing 23" which is fixed on the casing- 0f 'the engine 25, the said shaft being moved by the engine at the engine speed when .itlis a'two stroke motor, and with half speed in thlin'stance of a four stroke motor. On the cylindrical surface of the drum 2i 8, metal lamina or contact plate 25 having afltrapezoidal tile form is'attached and stands in'electric communication with a'central button or contact-2t which is fixed on'the' drum 2i. A mud or sleeve El made of an insulating material may slide longitudinally on the bearing 23 and its extensionZl supports two brushes; one of them, 28, is in constant contact with the button 25 and the other one 29, is inconstant contactiwith the cylindrical surface of the tion of the injection is obviously equal to the duration of the contact 1 between the trapezoidal lamina Ztandthebrush 29; if the drum of'theinterrupter rotates'sin thedirection of the arrow, thusidisplacin'glaxially' the mufi 21, the duration Oflthe contact (andconsequently that of the injection) varies, with the adjusting displacement oi. the muff, as regards the beginning of injection, ,while the end will be maintained uniform.

In the instance of multi-cylinder motors, the electric interrupter which controls the passage of the current in the several injectors is analogous to that just described, differing only by its having as many quidistant brushes, similar to brush 29, as there are cylinders, each of these brushes being electrically connected to one of the solenoids; and as the trapezoidal lamina is a single one only, the duration of the injection and its adjustments are identical for all cylinders.

In the instance of injection at low pressure into the intake air conduits (with two stroke as well as four stroke engines), the fuel-feeding ape.

paratus may be constituted of a tank, in which the fuel is stored at constant pressure by means of any self-regulating diaphragm pump or of another known type whatever; or this apparatus, in certain cases-as, for instance, when liquid acetylene is used-may be constituted by the common steel bottles provided with any pressure reducer whatever, preferably maintaining constant the absolute pressure of the air in the conduit and of the fuel in the injector, and thus, also the effective injection-pressure.

In the instance of injection at high pressure (internal'combustion motors), instead, the fuelfeeding apparatus should constitute a special device, both because it has to supply a constant injection pressure when the pressure of the air in the compression chamber is variable, and because 'or piston, whichis automatically driven by the gas pressure, acting upon the large-diameter surface, that is extant in the compression chamber and which piston, for its part, with the smalldiameter surface, applies pressure upon the fuel which is contained in the injector.

The whole of such an arrangement is shown in Fig. 3 in which the fuel-feeding apparatus is shown as a unitary part of the injector, in order to eliminate, .extemal pipings under pressure. The electromagnetic injector is like that already described with exception of the entrance of the fuel. At side of the injector casing 6 a pump casing 30 is fixed having connecting large and sinall recesses 3| and 32 within which'plays a double piston having large and small diameters at its ends 3| and 32. A restoring. spring 33 pushes this piston constantlyupward or in the direction of the larger diameter; at this side the piston recess 3|is in constant gas communication with the compression chamber 34 of the motor, and this by means of the passage 35; and at the side of the minor diameter, the recess 32 is in constant communication with the annular chamber I6 of the injector, and this by means of the'passage 36. A port 31 which at the end of the stroke is uncovered-by the small piston 32, puts the fuel chamber 38 below the piston 32 into communication with the pipe I!) and fuel tank 39 and a constantly open air hole or vent 40 serves for thedischarga'b'ack into the same tank 33 or place from the two pistons within the chamber 4| below the piston 3|. The areas of the two pistons 3| and 32 stand with one another in proportion equal to the proportion which it is desired to ob-' tain between the absolute pressure of the fuel and that of ignition.

In the case of a four stroke motor the operation may be as follows: during the suction stroke of the motor, the differential piston 3l--32 remains at the stroke-end, pushed by the spring 33 and sucked by the depression within the chamber 34; during the-compression stroke the increasing pressure in the chamber 34 overcomes the spring 33, the shifting piston 3 l32 advances and drives a bit of the fuel through port 31 back to the tank 39, and from the moment in which the piston 32,

covers the hole'31, a pressure is established in 38-36-l3' the value of which at any instant stands to that existing in the chamber 34 in the same proportion as that which exists between the areas of the large and small pistons 3| and 32. At the predetermined moment, the interrupter which is governed by the motor (analogous to that already described) makes the injector valve electromagnetically open, and the injection begins under fuel pressure; the absolute pressure of-the fuel increases automatically as that in the chamber 34, and thus the injection itself takes place at an efiective constant pressure; the injection ends abruptly with the discontinuation of the current. The pump piston 3 l32 remains still where it was left at this moment, until the end of the discharge of the motor; when the pressurev in'the cylinder 34 is ceasing, the piston is pushed back by the spring 33 and soon uncovers the hole 31, thus causing a connection to the chamber 38 which is fed again with fuel for the next cycle.

Consequently, the required injection pressure is applied upon the fuel well in advance of the opening of the injector and only terminates well after its closing so that there is abundant'latitude for the altering of the period of injection, with assurance of full pressure throughout the period.

In a two stroke motor the working is absolutely analogous.

The automatic pump at constant effective pressure as above described presents no piping subjected to elevated pressures, neither valves nor mechanical controls.

The wear of the piston 3l32 maintains a slight clearance which has no eifect on the precision of the injection, as the timing depends only upon the electric 'control of the injector While any leakages are compensated by the increase of displacement of the small piston 32. The clearance permits the piston to be restored by the spring.

Although there have been described several variations of structure and app ication, it will be I understood that the invention is not intended to belimited to these forms; as there could be devised many others, utilizing the novel principles and thu embodying the present invention.

What I claim and desire to secure by United States Letters Patent is: 1

1. In an apparatus of the kind described, having a, liquid fuel chamber, a retractible valve for controlling the delivery of fuel therefrom, a

and carrying an armature head, means guiding the stem for longitudinal movement, the valve to another place, the leakage losses which take and open positions, and a magnet coil surrounding said armature head and being adapted to be .the liquid, between closed and open'positions, so I that by the energizing or deen'erg'izing oi the coil the stem and valve are moved instantaneously from one position to the other swimmingly with- ,in the liquid, and without change of chamber volume, for ifuel delivery; and characterized further in that the magnet coil is enclosed by iron part including an end portion presenting a fixed central iron core in alignment with'said armature head which acts as a movable core and another end portion formed and arranged to guide the armature head with which the head is in sliding engagement at all times, whereby there is provided a substantially completemage netic circuit except for the slight gap between 4 g V r j aesaooe' stem'having a short movement between its closed the movable and fixed cores when the valve is closed.

2. An electromagnetically actuated valve means, the same having a magnet coil arranged to at- 5. tract a movable iron core which is connected to the valve thereby to open it; characterized in -'that' the movable core is located inside the coil, which is encasedin an iron housing presenting at one end a second iron core located within the 10 coil in alignment with the movable core and, at

the other end, being formed ,and arranged to guide themovable iron core which is in sliding engagement therewith at all times so as to present'a complete magnetic circuit without ap- 15 preciable air gap other than betweenthe two cores, whereby the movable core which is connected to the valve stem is, during the opening motion thereof, constantly under the influence oi the magnetic flux in said circuit, and forms a closing armature for such flux; and characterized further in that the parts moving with the valve stem are formed with channels adjacent a both ends of the valve stem which allow the free swimming. motion thereof within the liquid fuel 25 without altering the volume of the chamber.

OTTAVIO FUSCALDO: 

